Spring adjusting means therefor



Jan. 31, 1956 F. w. LIVERMONT PREDETERMINED TORQUE RELEASE WRENCH AND SPRING ADJUSTING MEANS THEREFOR 4 Sheets-Sheet 1 Filed March 9, 1953 INVENTOR. men/w 6U. L/VEPA/fi/VT ,arro/vzus F. w. LIVERMONT 2,732,747 PREDETERMINED TORQUE RELEASE WRENCH AND SPRING ADJUSTING MEANS THEREFOR Jan. 31, 1956 4 Sheets-Sheet 3 Filed March 9, 1955 I N VEN TOR.

FPHNK 0 L/I EEMO/VT QTTORNEVS 1956 F. w. LIVERMONT PREDETERMINED TORQUE RELEASE WRENCH AND SPRING ADJUSTING MEANS THEREFOR 4 Sheets-Sheet 4 Filed March 9, 1955 g g g g EFL g MN wb INVEN TOR. Fen/VA M4 01 52/110;-

United States Patent My invention relates to torque indicating wrenches which produce a visible or audible signal when applied torque reaches a predetermined value.' Wrenches of this type are adjustable so that the transmitted torque may be set for any desired value within the range of operation of the tool. This application is a continuation-inpart of my prior application filed January 19, 1953, for Torque Wrench, Serial No. 331,843, now abandoned.

It is the principal objectof this invention to provide a torque wrench of outstanding accuracy and yet which is rugged and compact in design. A more particular object is to provide a torque wrench having a novel I form of toggle action which substantially eliminatessliding friction and .provides superior performance. Another object is to provide a torque wrench which eliminates any pivotal or rotary connection between the handle and the work engaging part.

Another object is to provide a torque wrench of this type which employs a compression spring together with novel means for adjusting the initial position of the toggle mechanism to compensate for variations in dimensions and operating characteristics of the spring. In this way springs of commercial quality can be employed and it is not necessary to use premium price springs of guaranteed dimensions and performance characteristics.

Another object is to provide an improved form of spring adjusting mechanism together with an improved lock for maintaining the spring in adjusted position.

Other and more detailed objects and advantages will appear hereinafter.

In the drawings:

Figure l is a perspective view showing a preferred embodiment of my invention.

Figure 2 is a longitudinal sectional elevation thereof taken substantially on the lines 2-2 as shown in Figure 1.

Figure 3 is a sectional elevation partly broken away taken substantially on the lines 3-3 as shown in Figure 1.

Figure 4 is a sectional view taken substantially'on the lines 4-4 as shown in Figure 3,'theparts being shown in initial position. I 1 I Figure 5 isa sectional view similar to Figure 4 showing the parts in tripped position.

Figure 6 is a sectional view showing the spring adjusting and locking mechanism. 1

Figures 7, 8 and 9 are transverse sectional views take substantially on the lines '7'7, 8-8, 9-9, respectively, as shown in Figure 6.-

Figure 10 is an exploded view showing the manner of assembly of the toggle mechanism parts with respect to the case or housing.

Figure 11 is a perspective view showingtcertain of the parts of the spring adjusting and locking mechanism.

Figure 12 is a perspective view showing a portion of the case or housing.

Figure 13 isa sectional view showing a modified form of spring adjusting and locking mechanism.

Figure 14 is a sectional view taken substantially on the lines 14-14 as viewed in Figure 13.

Figure 15 is a sectional view taken substantially on the lines 1515 as viewed in Figure 13.

Figure 16 is an exploded view showing the manner of assembly of the parts of the device shown in Figure 13.

Referring to the drawings:

The torque wrench generally designated 10 includes a case or housing 11 provided with internal threads 12 at one end. These internal threads 12 are preferably formed as buttress threads and engage similar buttress threads 13 provided on the outer surface of the adjusting screw 14. A barrel 15 is fixed to they adjusting screw 14 in any suitable manner. As shown in the drawings, the barrel 15 may be provided with internal threads 16 which engage the external threads 17 on the adjusting screw 14.

A lock nut 18 also engages the external threads 17 and serves to clamp the barrel 15 and the adjusting screw 14 together against relative movement.

A block 19 is mounted for axial movement within the central opening of the case 11'. This block 19 has parallel sides 26 each provided with axially extending slots 21. Pins 22 extend through the slots 21 and are received in corresponding slots 23 formed in the central section 24 of the case 11. A spacer link 25 is provided with end portions 26 which loosely encircle the pins 22 and this spacer link is mounted within the block 19 between the parallel sides 24). An axially extending plug 27 is fixed to one end of the block 19 and this plug is received within the bore 28 of the flanged sleeve 29.

A coil spring 30 is mounted within the cylindrical portion 32 of the case 11 and extends axially therein. The coil spring 30 encircles part of the sleeve 29 and one end engages the shoulder'31. The other end of the spring engages the non-rotary element 33 of the spring adjusting assembly generally designated 34. The ends of the spring are preferably squared and ground. The action of the spring 30 is to apply a force tending to move the block 19 to the left as viewed in Figure 2. The magnitude of this force depends upon the position of the adjusting screw 14 with respect to the case 11.

A pin 35 is fixed to the block 19 near its forward end. A similar pin 36 is fixed on the tang 37 of the workengaging member generally designated'38. A pawl 39 is interposed between the 'pins 35 and 36. A portion of this pawl 39 extends within the block 19 between the side plates 20. A portion of the pawl also extends into an axial slot 40 provided in the tang 37. The pawl is provided with parallel olfset surfaces 41 and 42. The sur-v face 41 terminates in shoulders 43 and 44 and the surface 42 terminates in shoulders 45 and 46. The surface 41 engages the pin 36 and the surface 42 engages the pin 35. The surfaces 41 and 42 are ofiset in order to provide the shortest distance between them when the wrench is in its initial position so that the pins always have a uniform starting angularity'. The pins'35 and 36 roll on the pawl surfaces 42 and 41, respectively, when the'tang 37 shifts from the. initial position shown in Figure 4 to the tripped position shown in Figure 5.

The tang37 is provided with a slot 47 which receives a transverse roller 48. The roller also extends through aligned slots 49 in the forward end 50 of the case 11. The slots 47 and 49 are positioned at an angle with respect to the center line of the wrench and these slots are substantially aligned at the mid-point of movement of the tang 37. A recess 51 is provided in each side of the tang 37 and a ball 52 is positioned within each recess and engages the inner wall 53 of the case 11. The balls 52 roll within the recesses 51 to provide an anti-friction bearing between the tang 37 and the case 11. The tang 37 may be provided with laterally extending lugs 54 which project into aligned longitudinal slots 55 formed in the extreme forward end of the case 11. In normal use the lugs 54 do not contact the walls of the slots 55. The purpose of the lugs 54 and slots 55 is to resist anytwisting movement of the work-engaging member 38 with respect to the case 11.

The work-engaging member 38 may comprise a single 3. integral member for applying torque to a nut or bolt or, as shown in the drawings, the member 38 may coinprise a ratchet head for turning a square driver 56 in one direction only. The internal. construction of, this ratchet head forms no part of my present invention. A shift lever 57 may be provided if desired which can be moved to one of two positions for controlling the direction of ratcheting. In the position shown in the drawings, the shift lever 57 locks the driver 56 for clock- 'wise turning movement but permits it to ratchet back in the other direction. 1

A. set screw'58 is. threaded within the transverse bore 59 within the tang 37. This set screw contacts the inner surface 60 ofrthe forward end 50 of the case 11. An aperture 61 is provided in the case 11 through which a tool may be inserted to adjust the position of the set screw 58. In'order. to lock. the set screw in adjusted position; a ball 62 is placed against the inner end of the set screw and a. locking screw 63 is clamped against the ball. The reason for employing the ball 62 is to avoid the possibility of turning the set screw 58 by friction away from its adjusted. position when the locking screw 63 is turned home.

A sleeve 64 encircles the. central portion 24 of the case 11 and serves to prevent lateral displacement of the pins 22. The sleevealso provides a convenient location for imprinting of the manufacturers trademark and designation of the style and type of tool.

The spring adjusting assembly 34 includes the springcontacting non-rotary element 33, the ball carrier 65, the pilot head 66, the locking screw 67, the locking knob 68 and the spring 69. The screw 67 is threaded within the internal threads 7430f the adjusting screw 14. The. spring 69 acts to apply a friction drag to the knob 68 to prevent its being turned inadvertently when the barrel 15 is turned relative to the case 11. The pilot head 66 is also threaded to the screw 67 but is fixed in place thereon by any convenient means. For example, the pilot head 66 may be deformed as shown at 71 to prevent disassembly of the screw 67 and the pilot head 66. The parts 33 and 65 are provided with central clearance openings which are larger than the outer diameter of the screw 67. h

i As shown in Figures 7 and ll, the non-rotary element '33 is provided with a circumferential series of radially extending protuberances 72 and each of these protuberances engages an axially extending slot or groove 73 provided in the buttress threads 12 in the case 11. The element 33 is thus restrained against turning move ment within the case 11 but. is permitted to move axially thereof The back face 74 of the element 33 is provided with a circular series of indentations or dimples 75. Each of the indentations 75' is circular in shape and intersects the adjacent indentation. Each receives a portion of one of theballs 76011 the ball carrier 65. This carrier 65 constitutes a circular disc having a plurality of balls mounted in sockets 77 and extending laterally from the sides of the disc 65. The balls 76 are free to turn in the sockets 77. I prefer to employ five balls on the ball carrier and to provide twenty indentations 75' on the element 33. Twenty similar indentations or dimples 78 are provided on the forward end surface 79 of the adjusting screw 14. The balls 76 engage the recesses'78 and 75. The knob 68 may be turned to move the pilot head 66 in a direction away from the element 33. The adjusting screw 14' may then 7 be turned in either direction relative to the case 11 and during this turning movement the balls 76 "climb in and out of the indentations 78 and 75 so that the element 33 is caused to reciprocate axially within the case 4 I, therefore, stop at any one of ten relative angular positions but do not come to rest at intermediate locations.

A scale 80 calibrated in either foot-pounds or inchpounds is fixed on the outer surface of the cylindrical portion 32 of the case 11 and. cooperates with index 7 marks 81 provided on the forward end of the barrel. 15.

The positions of. the index marks 81 are such that they register with the central line of the scale 80 for any of the ten angular positions of the barrel 15 with respect to the case 11. From this description it will be understood that the-desired foot-pound or'inch-pound setting for the wrench is determined by turning the barrellS until the reading of the scale 80 and index marks 81 register the desired torque value. The locking knob 68 is then turned manually in a counter-clockwise direction, thereby clamping the. elements 33 and 65' between the pilot head 66 and the. adjusting screw 14.

Lining up of the index marks 81 with respectto the scale center line may readily be. accomplished byturning the barrel 15 with respect to the adjusting screw 14 and then fixing the. relative. position thereof by means of the lock nut 18.

Accidental disassembly of the adjusting screw 14 from the. case 111 is prevented by means of a split ring 82. mounted ina circumferential groove 83 on the end of the case 11. This, ring.- 82 is. installed after the barrel 15 has been assembled telescopically over the end of the case 11, but before the barrel is connected to the adjusting screw 14. When, the assembled barrel and adjusting screw are turned in, a direction to lengthen the spring 30 the shoulder 84 within the barrel 15 engages the split ring 82 to prevent complete disengagement of the buttress threads 12 and 13.

In operation, the locking knob 68 is released-and the barrel 15 is turned to the desired, torque setting; Turning of the barrel 15 causes the threads 13. on the adjusting screw 14 to advance into or retract out of the threads 12 on the housing or case 11. The movement of the end of the spring adjacent the element 33 is not uniform, however, but on the contrary the action of the balls 76 moving into and out of the indentations, 78 and 75 causes the adjacent end of the spring to oscillate axially. This action is very desirable since it takes alllost motion out of the assembly and ensures that the spring will exert'the proper force corresponding to the setting of the torque scales 80, 8L

When the barrel 15 has been turned to the-desired torque setting relative to the case 11, the locking knob 68 is turned manually to clamp. the parts 33 and between pilot head 66 and the forward end 'of the adjusting screw 14.. The barrel 15 is then fixed against rota tion withrespeetto.thecase11 because theballs 76 are prevented from moving between adjacent: indentations and 78. The spring 30, then applies a. predetermined axial 7 force to the block 19 through the shoulder 31 on the sleeve 29. The. small spring 85 within the bore 28 of larity of the pawl surfaces 41 and. 42. in. the initial.posi- 7 tion as shown inFigures 2 and. 4' is such as to apply a force on the tank 37 having a substantial componentv at right angles to the wrench axis. This component of the for e is applied by the adjusting screw 58 against the inner surface 6.0.0 of the. forward. portion 50 of the case 11. The axial'component of the force. acts; through the walls ofthe slot 47 against this, roller 48 and is absorbed against the walls of the. slots 49 in the case 11. Adjusting of the set screw 58 as described hereabove serves to change the angularity of the-positions of the pins 35 and 36 with respect to the longitudinal axis of the wrench and thereby changes the transverse component of the force exerted by the pawl 39 on the tank 37. Once properly adjusted, the set screw 58 remains the same position for all torque settingsofthe barrel 15 relative to the case 11. s 7

The square driver 56 is inserted intoa square opening in a driven part (not shown) and the shift lever 57 is moved to the position shown in the drawings. The user of the wrench then applies a torque load by swinging the wrench in a clockwise direction as viewed in Figure 2. As the torque load increases on the square'driver 56 the tang 37 and pawl 39 remain in the initial position and no motion occurs. When the applied torque load reaches the desired value, however, as determined by the setting of barrel 15 relative to the case 11, the force exerted by the pin 36 on the pawl 39 causes the parts to break or suddenly trip and move almost instantaneously to the tripped position shown in Figure 5. Once the pawl 39 starts to move, the angular-ity of the positions of the pins 35 and 36 changes so that the axial component of the applied force increases rapidly and the tank 37 suddenly shifts to the tripped position. The pins 35 and 36 roll along the surfaces 42 and 41 respectively and in tripped position they are spaced apart by a greater distance than their spacing in the initial position. This increase in spacing of the pins 35 and 36 causes the block 19 to move rearwardly to further compress the spring 30. The move ment of the block 19 causes the pins 22 to roll in the slots 21 and 23. V

It is desirable that not all of the torque load applied manually to the wrench be dropped. at the instant of break of the wrench, since such action would result in objectionable sudden movement of the hand of the wrench user, and furthermore would subject the moving parts of the wrench to undesirable shock loading of considerable magnitude. Enough torque load must be dropped, however, in order to provide a definite signal to the wrench user even though, for'example, the wrench is being used to tighten bolts on .a vibrating housing of an engine while it is running. I meet these confiicting requirements by proportioning the parts of the toggle mechanism so that approximately one-third of the torque load is dropped when the wrench parts break. This is suificient to provide a definite indication to the wrench user that the desired torque load has been applied and at the same time avoids objectionable motion of the wrench handle and avoids shock loading on the wrench parts. The slots 47 and 49 are set at an angle in order to reduce the force of the spring in tripped position and thereby assist in dropping approximately one third of the torque load when the wrench parts move to tripped position.

When the tank 37 begins to move relative to the wrench housing or case 11 the roller 48 rolls along the walls of the slots 47 and 49 andthis rolling action causes the flanges 86 to turn. The flanges may each be provided with a recess 87 which, in turning, provides a visible indication to the user of the wrenchthat the desired torque load has been achieved. i

It will be observed that sliding friction-has been eliminated in the working parts of the wrench. Thus the motion of the tang 37 with respect to the case 11 is accomplished by rolling action of the roller 48. Similarly, ind tion of the tang 37 with respect to the pawl 39 is accomplished by rolling of the pawl surface 41 with respect to the pin 36. Also the movement of the pawl 39 with respect to the block 19 takes place by rolling of the pawl surface 42 with respect-to the pin 35. The pins 22 roll on the walls of the aligned axial'slots 21 and 23.-Therefore,'the performance of thezwrench is substantially unaffected by presence or absence of lubricant on the various moving parts.

The wrench may be used as an ordinary ratchet wrench without the torque feature simply by screwing the barrel 15 in a direction to compress the spring 30. The wrench then may be used in either direction and the shift lever 57 may be actuated to turn the square driver 56 in either direction and allow it to ratchet back in the other di- 'rection.

In the modified form of my invention shown in'Figures 13 to 16 the compression spring 30 is mountedv within a modified housing or case 11a. This case 11a is provided with internal threads 12a which terminate at the end of the case 11a. An axially extending slot 101 is provided in the case 11a but the slot terminates short of the end 100. A bushing 102 is provided with external threads 103 engaging the threads 12a. This bushing 102 is fixed to the case by means of a set screw 104 which extends through the axial slot 101.

A sleeve 105 is slidably mounted on the cylindrical surface 106 of the case 11a. The barrel 15a is mounted to turn on the outer surface of the sleeve 105 and is provided with an integral flange or hub portion 107 which is internally threaded to receive the externally threaded portion 108 of the adjusting screw member 109. A lock nut 110 serves to prevent relative movement between the barrel 15a and the adjusting screw member 109.

The adjusting screw member 109 extends axially through a central opening 111 in the bushing 102 and is provided with a central integral enlargement or flange 112. The forward portion of the member 109 is provided with left-hand screw threads 113. These screw threads 113 mate with internal threads 114 provided on the non-rotary nut 115. A set screw 116 engages the nut 115 and extends through the axial slot 101 so that the nut 115 is restrained from rotation but is permitted to travel axially. The set screw 116 also extends into an aperture 117 provided on the sleeve 105 so that the sleeve travels axially with the nut.

A series of balls 76:: is mounted in a carrier disc 65a and positioned between the abutment or fiange 112 and the'bushing 102. The surface 118 of the flange and the surface 119 of the bushing are each provided with a series of dimples or indentations 120 which are similar to the indentations 75 and 78 previously described. Turning movement of the barrel 15a causes similar turning movement of the adjusting screw member 109 with the result that the balls 76a climb in and out of the indentations- 120 thereby causing the adjusting screw member 109 to reciprocate axially through a short distance. Turning movement of the member 109 causes the nut 115 to travel axially thereby changing the energy stored in the spring 30. Axial movement of the nut 115 is reflected in axial movement of the sleeve 105. The sleeve 105 may be provided with suitable indicia on its outer surface forming a scale which cooperates with the end surface 121 of the barrel 15a to furnish an indication of the torque load setting of the wrench.

In order to lock the spring adjusting mechanism at any desired torque setting, I provide means for restricting axial movement of the member 109 .with respect to the bushing 102.; As'shown, this means includes a locking knob 122 rotatably supported within a recess 123 near the end of the barrel 15a. A split retainer ring 124 prevents the knob 122 from moving out of the recess. A plurality of parallel pins 125 are slidably mounted in axially extending apertures formed in the hub 107 of the barrel 15a. The pins bear against a Washer 126 at one end and against another washer 127 at the other end. A friction washer 128 may be interposed between the washer 127 and the knob 122 to provide a friction drag. When the knob 122 is turned relative to the externally threaded portion 108 of the member 109, the effect is to clamp-the pins 125 and washers 126, 127 and 128 between the knob 122 and the bushing 102. This in turn prevents axial movement of the member 109 and prevents the balls 76a from moving relative to the indentations or dimples 120. The barrel 15a is thus locked against turning in either direction.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details herein set forth, but my invention is of the full scope of the appended claims.-

V I claim:

greens 'l-. In a torque wrench, the combination of: a workengaging member having a laterally projecting part, a housing, a block mounted for axial movement within the housing, resilient means acting to move theblock axially, means including a transverse roller remote from the work engaging member connecting the said part to the housing, and toggle means including a tiltable pawl interposed between the block and the said part.

2. In a torque wrench, the combination of: a workengaging member having a laterally projecting tank, a housing, a block mounted for axial movement Within the housing, resilient means acting to move the block axially, means including a transverse roller remote from the work-engaging member connecting the tang to the housing, the housing and tang each having a transverse element mounted thereon, and a pawl interposed between the block and the tang having surfaces engaging said elements. I 3. In a torque wrench, the combination of: a Workengaging member having a laterally projecting tang, a housing, a block mounted for axial movement within the housing, a spring within the housing acting to move the block axially, means including a transverse roller remote from the work-engaging member connecting the tang to the housing, the housing and tang each having a ransverse pin fixed thereon, and a pawl inteiposed be tween the block and the tang and having parallel surfaces engaging said pins.

4. In a torque wrench, the combination of: a workengaging member having a laterally projecting tang, a housing, a block mounted for axial movement within the housing, a spring within the housing acting to move the block axially, means including a transverse roller remote from the work-engaging member connecting the tang to the housing, the housing and'tang each having a transverse pin fixed thereon, a pawl interposed between the block and the tang and having parallel surfaces engaging said pins, and means for adjusting the force exerted by the spring.

5. In a torque wrench, the combination of: a workengaging member having a laterally projecting tang, a housing, a block mounted for axial movement within'the housing, a compression spring within the housing acting to move the block axially, means connecting the tang to the housing, including a transverse roller received within aligned slots on the tang and housing; the tang and housing each having a transverse pin mounted thereon, and a pawl having spaced surfaces interposed between said pins.

6. In a torque wrench, the combination of: a housing, a work-engaging member having a tang projecting into the housing and adapted to swing transversely therein, a block, roller means mounting the block for axial movei ment within the housing,.a spring within the housing acting to move the block axially, means including a transverse roller remote from the work-engaging member connecting the tang to the housing, and toggle means operatively interposed between the tang and the block.

7. In a torque wrench, the combination of: a housing, a worloengaging member having a tang projecting into the housing and adapted to swing transversely therein, a block, roller means mounting the block for axial movement within the housing, a spring within the housing acting to move the block axially, means including a transverse roller remote from the work-engaging member connecting the tang to the housing, the housing and tang each having a transverse pin mounted thereon, a pawl having parallel surfaces engaging said pins, and means for adjusting the force. exerted by the spring.

8. In a torque wrench, the combination of: a housing having an open end, awork-engaging member having a tang projecting into the open end of the housing and.

the block axially, the tang and housing'having aligned slots, a transverse roller positioned in said aligned slots, the housing and'tang each having a transverse element thereon, and a tiltajblepawl interposed between the block and the tang and having spaced surfaces engaging said elements. I I

9; In a torque wrench, the combination of a housing, a work-engaging member having a tang, a block, roller means mounting the block for axial movement within the housing, a spring within" the housing acting to move the block axially, the tang'and housing having aligned slots, a transverseroller positioned in said aligned slots, the housing and tang each having a transverse pin mounted thereon, and a tilable. pawl interposed between the said transverse pins, and having rolling contact therewith. V

10; In a torque wrench, the combination of: a housing, a work-engaging member having a tang projecting into the housing and adapted-to swing transversely there in, a block, resilient means within the housing acting to move the block axially, the tang and housing having aligned slots, a transverseroller positioned in said aligned slots, the housing and tang" each having a transverse pin mounted thereon, and atiltable pawl interposed between the said transverse pins, the pawl acting to hold the pins at an angle with respect to the axis of the block under noload conditions, and to permit the tang pin to swing in a direction to reduce such angle when the torque load on the work-engaging, member reaches a predetermined value.

11. In a torque wrench, the combination of: a housing 7 angle with respect to the axis of the block under no-load conditions, and to permit the tang pin to swing in a direction to reduce such angle when the torque load on the work-engaging member reaches a predetermined value.

12. In a torque wrench, the combination of: a housing, a work-engaging member having a tang projecting into the housing and adapted to swing transversely therein, a block, a spring acting to move'the block axially, the tang and -housing having aligned slots disposed at an angle to a transverse plane a transverse roller positioned in said aligned slots, the housing and tang each having a transverse pin fixed thereon, a tiltable pawl interposed between the block and the tang and having parallel surfaces engagingsaid pins, the pawl acting to hold the pins at an angle with respect to the axis of the block under noload conditions, and to permit the. tang pin to swing in a direction to reduce such angle when the torque load on the work-engaging member reaches a predetermined value.

13. In a torque wrench, the combination of: a housing, a work-engaging member having a tang projecting into the housing and adapted to swing transversely therein, a..block, a spring acting to move the block axially, the tang and housing, having aligned slots, a transverse roller positioned in said aligned slots, adjustable means for limit.

ing swinging movement of'the'tang relative to the housing in one direction, the housing and tang each having a transverse pin fixed thereon, a tiltable pawl interposed between the block and the tang and having parallel surfaces engaging said pins, the pawl acting to hold the pins at an angle with respect to the axis of the block under noload conditions, and to permit the tang pin to swing in a direction to reduce such angle when the torque load on the work-engaging member reaches a predetermined value. 14'. In a torque wrench, the combination of: a housing having an open end, a work-engaging member having a tang projecting into the open end of the housing and adapted to swing transversely therein, a block, roller means mounting the block for axial movement within the housing, a spring within the housing acting to move the block axially, the tang and housing having aligned slots, a transverse roller positioned in said aligned slots, adjustabl means on the tang engageable with an inner surface of the housing for limiting swinging movement of the tang relative to the housing in one direction, the housing and tang each having a transverse pin mounted thereon, and a tiltable pawl interposed between the said transverse pins, the pawl acting to hold the pins at-an angle with respect to the axis of the block under no load conditions, and to permit the tang pin to swing in a direction to reduce such angle when the torque load on the work-engaging member reaches a predetermined value. v

15. In a torque wrench, the combinationof: a workengaging member, a housing, toggle meansoperatively interposed between the housing and ,the'work-engaging member, a non-rotary element guided for axial movement within the housing, a compression spring within the housing interposed between said non-rotary element and said toggle means, an adjusting'screw having a threaded connection relative to the housing, said element having a face provided with a circular series of indentations, a plurality of balls interposed between said face and said adjusting screw and received within said indentations, whereby turning movement of the adjusting screw relative to the housing in either direction alternately contracts and extends the spring as the balls more from one indentation to the next.

16. In a torque wrench, the combination of: a workengaging member, a housing, toggle means operatively interposed between the housing and the work-engaging member, a non-rotary element guided for axial movement within the housing, a compression spring Within the housing interposed between said non-rotary element and said toggle means, an adjusting screw having a threaded connection relative to the housing, said adjusting screw having a face provided with a circular series of indentations, a plurality of balls interposed between said face and said non-rotary element and received within said indentations, whereby turning movement of the adjusting screw relative to the housing in either direc tion alternately contracts and extends the spring as the balls move from one indentation to the next.

17. In a torque wrench, the combination of: a workengaging member, a housing, toggle means operatively interposed between the housing and the work-engaging member, a non-rotary element guided for axial movement within the housing, a compression spring within the housing interposedhetween said non-rotary element and said toggle means, an adjusting screw having a threaded connection relative to the housing, said element and said adjusting screw having confronting faces each provided with a circular series of indentations,.a plurality of balls interposed between said confronting faces and received within said indentations, whereby turning movement of the adjusting screw relative to the housing in either direction alternately contracts and extends the spring as the balls move from one indentation to the next. v

18. In a torque wrench, the combination of: a workengaging member, a housing, toggle means operatively interposed between the housing and the work-engaging member, a non-rotary element guided for axial movement within the housing, a spring within the housing interposed between the said non-rotary element and said toggle means, an adjusting screw having a threaded connection relative to the housing, said element and said adjusting screw having confronting faces eachiprovided with a circular series of indentations, a plurality'of balls interposed between said confronting faces and received I10 within said indentations, and releasable clamp means on the adjusting screw for preventing relative axial movement of said element and adjusting screw.

19. In a torque wrench, the combination of: a workengaging member, a housing having an inner surface provided with axially extending grooves, toggle means operatively interposed between the housing and the workengaging member, a non-rotary element engaging said grooves for axial movement within the housing, a spring within the housing interposed between said non-rotary element and said toggle means, an adjusting screw having a threaded connection relative to the housing, said element and said adjusting screw having confronting faces, at least one of the faces being provided with a circular series of indentations, a plurality of balls interposed between said confronting faces and received within said indentations, and releasable clamp means on the adjusting screw having an element accessible exteriorly of the housing for preventing relative axial movement of said element and adjusting screw.

20. In a torque wrench, the combination of a work: engaging member, a housing, toggle means operatively interposed between the housing and the work-engaging member, a non-rotary element guided for axial movement within the housing, a spring within the housing interposed between said non-rotary element and said toggle means, an adjusting screw having a threaded connection relative to the housing, said element and said adjusting screw having confronting faces, at least one of the faces being provided with a circular series of indentations, a plurality of balls interposed between said confronting faces and received within said indentations, and releasable clamp means on the adjusting screw for preventing relative axial movement of said element and adjusting screw, said clamp means including a part threadedly connected to the adjusting screw and extending axially thereof, said part having a shouldered head engageable with the non-rotary element, and a knob fixed to said part and accessible exteriorly of said housing.

21. A torque wrench case or housing formed from a single integral length of tubing, the case being open at both ends, a rear portion of the case being cylindrical and provided with internal threads, an intermediate portion of the case being partially flattened to provide parallel walls, the walls having axially extending slots, and a forward portion of the case being flattened to a greater extent to provide greater internal width and having a transverse slot therein.

22. In a torque wrench, the combination of: a housing formed from a single integral length of tubing open at both ends, a rear portion of the housing being cylindrical and provided with internal threads, an adjusting screw threadedly connected relative to the housing at the internally threaded portion thereof, an intermediate portion of the housing being partially flattened to provide parallel walls, the walls having axially extending slots, a block mounted within said intermediate portion of the housing and guided for axial movement along said slots, a forward portion of the-housing being flattened to a greater extent to provide greater internal width and having a transverse slot therein, a work-engaging member having a tang projecting into the open end of said forward portion of the housing, a roller extending through the tang and received in said transverse slot, the tang being adapted for transverse swinging movement within said forward portion of the housing, toggle means operatively interposed between the tang and said block, and a compression spring positioned within said housing between the adjusting screw and said toggle means.

23. In a torque wrench, the combination of: a workengaging member having a laterally projecting tang, a housing, a block mounted for axial movement within the housing, a spring-within the housing acting to move the block axially, means including a transverse roller remote from the work-engaging member connecting the tang to the housing, the housingand tang each having a transverse pin fixed thereon, and a pawl interposed between the block and the tang and having parallel offset; surfaces each terminating in shoulders, each of said pins being engageable with one of the surfaces and shoulders.

24. In a torque wrench, the combination of: a workengaging member, a housing element, toggle means operativelyinterposed between the housing element and the work-engaging member, a non-rotary element guided for axial movement within the housing element, a compression spring within the housing element interposed between said non-rotary element and said toggle means, an adjusting screw having a threaded connection relative to one of said elements, said adjusting screw and the other of said elements having confronting faces, at least one of said faces being provided with a circular series of indentations, a plurality of balls interposed between said confronting faces and received Within said indentations, whereby turning movement of the adjusting screw relative to the housing, elementin either direction alternately contracts and extends the spring as the balls move from one indentation to the next.

25. In a torque wrench, the combination of: a workengaging member, a housing element, toggle means operatively interposed between the housing element and the work-engaging member, a non-rotary element guided for axial movement within the housing element, a spring within the housing element interposed between said nonrotary element and said toggle means, an adjusting screw having a threaded connection relative to one of said elements, said adjusting screw and the other of said elements having confronting faces, at least one of said faces being provided with a circular series of indentations, a plurality of balls interposed between said confronting faces and received within said indentations, and releasable clamp means for preventing relative axial movement of said non-rotary element and adjusting screw.

26. In a torque wrench, the combination of: a workengaging member, a housing element, toggle means operatively interposed between the housing element and the work-engaging member, a non-rotary element guided for axial movement within the housing element, a spring within the housing element interposed between said nonrotary element and said toggletmeans, an adjusting screw having a threaded connection relative to one of said elements, said adjusting screw and the other of said elements having confronting faces, at least one of said faces being provided with a circular series of indentations, a plurality of balls interposed between said confronting faces and received within said indentations, and releasable clamp means including a part mounted on the adjusting screw and accessible. exteriorly of the housing element for preventing relative axial movement of said non-rotary element and adjusting screw.

27. In a device for changing the energy stored ina compression spring, the combination of: a housing element, a non-rotary element guided for axial movement within the housing element and engaging one end of the spring, an adjusting screw having a threaded connection relative to one of said elements, said adjusting screw and the other of said elements having confronting faces, at least one of said faces being provided with a circular series of indentations, a plurality of balls interposed between said confronting faces and received within said indentations, whereby turning movement of the adjusting screw relative to the housing element in either direction alternately contracts and extends the spring as the balls move from one indentation to the next.

28-. In a device for changing the energy stored in a spring, the combination of: a housing, a non-rotary element guided for axial movement within the housing and engaging one end of the spring, an adjusting screw having a threaded connection relative to the, housing, said non-rotary element and said adjusting screw having confronting faces, at least' one of said faces being provided with a circular seriesof indentations, a plurality of balls interposed between said confronting faces V and. received withinsaidindentations, whereby turning movement of the adjusting screw-- relative to the housing ineither direction alternately contracts and extends the spring as the balls move from one indentation to the next. r

29. Ina device for changing the energy stored in a spring, the combination of: 'a housing, a non-rotary element guided for axial movement within the housing and engaging one end of the spring, an adjusting screw having a threaded connection relative to the housing, said nonrotary element and said adjusting screw having confronting faces, at least one of said faces being provided with a circular series of indentations, a plurality of balls interposed between said confronting faces and received within said indentations, and, releasable clamp; means on the adjusting screw for preventing relative axial movement of said non-rotary element and adjusting screw.

30. In a device for: changing the energy stored in a a compression spring, the combination of; a housing, anonrotary nut guided for axial movement within the housing and engaging; one end of the compression spring, a stationary part fixedrel'ative to the housing, anradjusting screw having a threaded connection with the nut, said stationary part and said adjusting screw having confronting faces, at least one of said faces being provided with a circular series of indentations, a plurality of balls interposed between said confronting faces and received within said indentations, whereby turning movement of the adjusting screw relative to the housing in either direction alternately contracts and extends the spring as the balls move from one indentation to the next.

31. In a device for changing the energy stored in a compression spring, the combination of: a housing, a nonrotary nut guided for axial movement within the housing and engaging one end of the compression spring, a stationary part fixed relative to the housing, an adjusting screw having a threaded connection with the nut, said stationary part and said adjusting screw having confronting faces, at least one of said faces being provided with a circular series of indentations, aplurality of balls interposed between said confronting faces and received within said indentations, and releasable clamp means en aging the adjusting screw for preventing relative axial movement of the adjusting screw and saidstationary part,

32. In a torque wrench, the combination of: a work engaging member, a housing, toggle means operatively interposed between the, housing and the work-engaging member, a non-rotary nut guided for axial movement within the. housing, a compression spring within the housing interposed between said. non-rotary element and, said toggle means, a stationary part fixed relative to the housing, an adjusting screw having: a threaded connection with the nut, said stationary part and said adjusting screw having confronting faces, at least one of said faces being provided with a circular series of indentations, a plurality of balls interposed between said confronting faces and received within said indentations, and releasable clamp means connected to the adjusting screw for preventing relative axial movement of said stationary part and ad justing screw.

References Cited in the file of this patent UNITED STATES PATENTS 1,860,871 Pouliot May 31, 1932 1,881,633 Johnson Oct. 11, i382 2,300,652 Cooney Nov. 3, 1942 2,365,486 Morris n Dec. 19, 134-4 2,374,217 Larson e'tal Apr. 24, 1945 2,396,040 Darling Mar. 5, 1946' 

